Abstract
Processing of fearful facial expressions occurs via both cortical and subcortical routes. Evidence from event related potential (ERP) research suggests that fearful facial expression influences neural activity as early as 100ms. More specifically, these early activations appear to reflect processing of low spatial frequency information via a magnocellularly driven subcortical route. Based on evidence of differences in visual processing across the autistic spectrum, we suggest that rapid processing of low spatial frequency fearful faces may vary as a function of autistic tendency. Here we compare ERP responses to low and high spatial frequency fearful expressions for groups of neurotypical individuals with low cf high levels of autistic tendency. Visual ERPs were collected for two (neural/fearful) by two (low/high spatial frequency) sets of hybrid face stimuli, all of which were matched for luminance and root-mean-square contrast. Consistent with previous evidence, ERP P100 response amplitudes were greater for fearful cf neutral faces and this effect was specific to low-spatial frequency fearful expressions. Interestingly, processing of low and high spatial frequency fearful expressions differed across AQ groups. In the low AQ group, N170 amplitude was greater for low-spatial frequency fearful expression, whereas in the high AQ group, N170 amplitude was greater for high-spatial frequency fearful expression. These results suggest that even within the neurotypical population, autistic tendency affects subcortical processing of low-spatial frequency fearful expression. Hence, differences in emotional face processing across the autistic spectrum may be explained by early visual processing biases in the magnocellular and parvocellular pathways.
Meeting abstract presented at VSS 2016